Stud driving tool



April 4, 1961 s. H. BROUGHTON STUD DRIVING TOOL 5 Sheets-Sheet 1 Filed Nov. 17, 1955 I m, a

riff/ll!!! If", IIIIIIIISIIIIIIE INVENTOR. SIDNEY H. BROUGHT CW AT TORNEV 5 Sheets-Sheet 2 STUD DRIVING TOOL S. H. BROUGHTON A ril 4, 1961 Filed NOV. 17, 1955 INVENTOR. SIDNEY H. BROUGHTON hm Nm ATTORNEY April 4, 1961 s. H. BROUGHTON 2,977,598

STUD DRIVING TOOL Filed Nov. 17, 1955 5 Sheets-Sheet 3 f/GL .9 73

48 72 74 INVENTOR.

SYDNEY h. BROUGH TON A T TOPNEV April 4, 1961 s. H. BROUGHTON STUD DRIVING TOOL 5 Sheets-Sheet 5 Filed Nov. 17, 1955 N m6 NU mm B H v, E N w ATTORNEY 2,977,598 STUD nnrvmo 'roor.

Sidney Hubert Broughton, Portland, reg., assignor, by

mesne assignments, to Omark Industries, Inc., a corporation of Oregon Filed Nov. 17, 1955, Ser. No. 547,351

6 Claims. (Cl. 1-106) The present invention relates to explosively actuated stud driving tools, and is concerned more particularly with providing a tool of improved construction providing a desirable break-open action, automatic cartridge ejection, and a desirable sectional construction to promote easy assembly and disassembly.

It is the general object of the invention to provide an improved explosively actuated stud driving tool having a side opening action to facilitate loading of the tool with a stud and cartridge.

Another object of the invention is to provide an improved tool which is locked against firing, until it is fully conditioned for firing.

Another object of the invention is to provide a stud driving tool including a replaceable firing pin insert.

Another object of the invention is to provide a stud driving tool including a keyhole type sear release.

Another object of the invention is to provide a stud driving tool which is easy to assemble or disassemble.

Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, as illustrated in the accompanying drawings, in which:

Figure l is a longitudinal vertical sectional view of the tool.

Figure 2 is a detail vertical sectional view taken in planes indicated by approximately the line 2-2 in Figure 1.

Figure 3 is a detail vertical sectional view taken as indicated by the line 3-3 in Figure 5.

Figure 4 is a side elevational view of tool, partially in vertical section, showing the tool pressed against a surface in which a stud is to be installed ready for firing action.

Figure 5 is a detail horizontal sectional view taken in a plane indicated by the line 55 in Figure 3.

Figure 6 is a detail sectional view illustrating the extractor mechanism and taken in a plane indicated by the line 66 in Figure 5, the top of the tool as viewed in Figs. 1 and 4 being to the left in Fig. 6. t

Figure 7 is a fragmentary side elevational view, partially in vertical section, similar to a portion of Figure 4, and showing the tool as conditioned while pulling the trigger, i.e. at the moment of firing.

Figure 8 is a perspective view of the tool showing its side opening or breaking action, a portion of the action housing being broken away to show the lower portion of the breech block.

Figure 9 is a detail vertical sectional view taken in a plane indicated by the line 9-9 in Figure 7.

Figure 10 is a fragmentary plan view showing the action of tool in breaking open and ejecting a cartridge, a portion of the action housing being broken away to show the upper portion of the breech block.

Figure 11 is a fragmentary view of the tool showing it in use as extended for firing into a recessed chamber such as a junction box.

5 Patent Figure 12 is a side elevational view of the barrel housing assembly with portions broken away.

Figure 13 is a side elevational view of the action housing assembly with portions broken away.

Figure 14 is a detail view with parts broken away as indicated by the line 14-14 in Figure 1.

Referring to thedrawings and particularly Figures 1 and 4 thereof, the tool has a rear or handle portion including a handle part 2t) and a firing action portion 21 normally secured to the handle part 29 by a plurality of capscrews 22, and has a front or barrel portion including a barrel 23, a barrel housing assembly 24 (Fig. l), and a deflector pad or safety shield 26. The tool is used to fire a stud 27 shown in the barrel 23 in spaced relation with respect to a cartridge 28, the stud having a retainer sleeve 29 thereon. The front and rear portions of the tool have an open or loading position relative to each other and also a closed position relative to each other. In the closed position, the firing action portion 21 of the rear portion of the tool is in alignment with the longitudinal axis of the barrel and the handle part extends at an angle to such longitudinal axis. The front and rear portions of the tool are pivotally connected to each other as described below in detail to enable the front and rear portions to be pivoted relatively to each other between the closed position and the open or loading position.

The handle part 20 of the tool includes a frame or casting 31, having a rubber covering 32 thereon and being recessed at 33 to reduce the weight and provide storage space for an accessory. The handle casting 31 is apertured to receive a sleeve 34 providing a guide housing for a firing pin spring 36 and a firing pin 37. The firing pin 37 is provided with a flange 38 which abuts an end wall of an action housing assembly 39 which forms part of the firing action portion and which is referred to in detail hereinafter. On its underside the handle casting 31 is provided with a recess 41, to receive a recessed trigger 42 which is pivoted on a pin 42:: secured by a pair of screws 43 (Figure 2) to the assembly 39. The trigger 42 is subjected to the action of a torsion spring 44 having one arm seated against the trigger 42, a coil surrounding the pin 42a, and another end seated in a suitable aperture in the cap 45 of the action housing assembly 39. The trigger 42 has a stop surface 46 which is normally received in a suitable slot in the action housing assembly 39 and abuts a surface thereof. The trigger 42 is also provided with an actuating finger 47 for co-operation with keyhole type sear 48, but normally spaced rearwardly therefrom as referred to in detail hereinafter.

The action housing assembly 39 (Figures 1, 4 and 13) includes an outer sleeve or tube 51, which is silver soldered about an inner sleeve 52 having respective upper and lower extensions 53 which are spaced apart at each side by respective slots 54 and 56 to co-operate with other parts of the tool. The third member of the action housing assembly 39 is the action housing cap 45 previously referred to, which provides a mounting for the trigger 42, and the three parts including the action housing cap 45, and the two sleeves 52 and 51 are secured together as a unit by silver soldering.

The barrel housing assembly 24 (Figures 1 and 12) comprises a barrel housing tube 61, a barrel housing ring or plate 62, and a barrel housing tang mamber 63 which includes a ring portion from which extend opposite long and short tangs 64 and 65, these tangs 64 and 65 fitting in the similarly lengthened grooves 56 and 54 respectively of the action housing sleeve 52. These parts 61, 62 and 63 are secured together by silver soldering to function as a unit. Contained within the action housing assembly 39 is a breech block 66 in the form of a yoke (Figures 1, 3 and 10) whose two spaced yoke portions 67 and 68, fit within the extensions 53 of the action housing assem- Fatented Apr. 4, 1961 ac /Mae bly 39. The rear end portion 69 of the breech block66 connects the yoke portions 67 and 68 and is provided with a threaded aperture to receive a firing pin insert 70 as shown in Fig. l, whose'recessed inner surface corresponds to the shape of the nose of the firing pin 37. The firing pin is guided in a boss of a firing guide 71, which is secured to the rear end portion 69 of the breech block 66 by the screws 72 (Figs. 2 and 9). A firing pin spacer plate 73 (Figs. 2, 4 and 9) is provided between the firing pin guide 71 and the breech block 66 to provide clearance spacing for the slidably mounted sear or sear plate 48. The sear 48 has a keyhole slot 48a co-operating with the firing pin 37 (Figures 2 and 9) and is springurged upwardly to locking position bya pair of springs 74 engaged beneath the lateral extensions 48b (Figure 2) of the sear plate, and seated on aligned shoulders 73a of the spacer plate 73.

The yoke portions 67 and 68 (Figures 1, 3 and 8) of the breech block 66 embrace a barrel block 76, which is pivotally connected to the yoke portions of the breech block at one side of the barrel 23 (Figure by means of a pivot pin 77, which as shown in Figure 5 seats also in an arcuate recess in the barrel 23. A dowel pin 78 engages in a similar arcuate recess in the barrel 23 and extends through an aperture in the barrel block 76, the pins 77 and 78 securing the barrel 23 in the barrel block 76. It will be noted from Figures 1, 4 and 8 that the handle part 29 of the tool has a portion which extends at an angle to the longitudinal axis of the barrel 23 of the tool so as to define a plane which passes through the longitudinal axis of the barrel and centrally through such portion of the handle. It will be further noted that the pivot pin 77 between the breech block 66 and the barrel block 76 is spaced laterally from the longitudinal axis of the barrel, is parallel to the plane just mentioned and is also perpendicular to such longitudinal axis.

A simple, quick releasable lock is provided to enable separation of the rear portion of the tool including the action housing assembly 39 and firing pin 37 from the remainder of the tool.

The breech block 66 carries in its rear lower portion 69 a stripping lock plunger 81 (Figure l) which normally seats in an elongated slot 82a in the action inner housing sleeve 52, and normaliy overlies an access aperture 82 in the outer action sleeve 51. The stripping plunger 81 is recessed to receive a spring 83 which also seats against a suitable surface of the breech block 66. The plunger 81 serves to hold the handle part and action housing assembly 39 in assembled relationship. I 'By inserting a suitable pointed instrument such as the stud'27 through the aperture 82 (Fig. 1), and forcing the plunger 81 from the elongated slot 82:1 the rear or handle part of the tool including the action housing assembly 39 can be separated from the remainder of the tool. The elongation of the slot 82a provides for a telescoping movement of the tool against the action of a main spring 86 which is seated at one end against a shoulder 87 of a barrel tube 88, and at the other end is seated against the barrel housing plate 62, the spring 86 being compressed upon conditioning of the tool for firing as later described.

The rear face of the barrel block 76 (Figures 3, 5, 6 and 8) and of the barrel 23 are recessed to receive the head 91 of an extractor 92 for the cartridge, this extractor having a shank slidably mounted in the block 76 and having a flat sided pin 93 projecting laterally there from through a suitable elongated aperture in the barrel block 76. The barrel block 76 also has a longitudinal hole-95 which receives an extractor spring 94 which urges an extractor spring plunger 96 (Fig. 3) into a milled slot in the pin 93 thus retaining the pin in place. The spring 94 normally maintains the extractor seated as seen in Figures 3, 5, and 6, with its recessed head 91 in overlapping engagement with a cartridge receiving recess 98 (Fig. 6) in the barrel 23, the extrac or he d 1 havinga 4 mating recess 91a. Thus the extractor is in constant contact with the cartridge which it is to eject when the cartridge is in place, and the extractor is spring-urged to retracted position.

As seen in Figures 3 and 10, one yoke portion 67 of the breech block 66 has a flat triangular recess 101 which contains a pivoted pawl 162 carried by a pin 163 and which pawl is restrained in its movement by the engagement of spaced portions thereof with the side wall 101a of recess 191. During the opening of the tool by movement of the breech block 66 about the pivot pin 77 with respect to the barrel block 76 (Figure 10), the pawl 102 carried by the breech block 66engages the beveled projecting end of the fiat-sided pin 93 carried by the extractor 92 to move the extractor to the position shown in Fig. 10. This effects cartridge ejecting movement of the extractor head 91 and the'pawl MP2; is then carried past the pin 93 during further opening movement so that the extractor 92 can be restored to its retracted position by its spring 94. Upon return movement of the breech block by pivoting about the pin 77, the pawl 162 can pivot to a limited extent in a clockwise direction in Fig. 10 about the pin 103 so that the pawl can pass the pin 93. Even when the extractor 92 is in its retracted position, the pin 93 is sufiiciently spaced from the left end of the barrel block 76 in Fig. 10 that the pawl passes the pin 93 as the breech block is rotated counterclockwise in such figure. After the pawl passes the pin 93 continued movement of the breech block causes the lower left portion of the pawl in Fig. 10 to engage the surface against which the left end of the breech block abuts when in its firing position. Such surface is the left surface of the barrel housing ring or plate 62 shown most clearly in Fig. 1. This pivots the pawl in a counterclockwise direction in Fig. 10 to position it to again engage the pin 93 when the tool isopened. When the pawl engages the pin during the opening of the tool, the pawl further pivots in a counterclockwise direction to the position shown in Fig. 10.

Normally the tool is latched or locked against breaking or opening movement by virtue of the engagement of the tang 64 (Figures 5 and 8) underneath the outer sleeve 51 of the action housing assembly 39. When it is desired to break the tool and open it for cartridge ejection and reloading, the barrel housing assembly 24 is grasped in onehand and the handle 31 in the other and the barrel housing assembly 24 is moved toward the muzzle against the tension of spring 86 so as to free the tang 64 from the sleeve 51, the tang 64 thus constituting an element slidably carried by the front portion of the tool on side of the tool opposite the pivot pin 77 for movement longitudinally of the front portion so as to releasably engage under the sleeve 51. With the parts thus conditioned, they can be pivoted about the hinge pin 77 and the barrel block 76 made accessible for re loading. 1

The barrel housing assembly 24 (Figure 1) is encased in a strippable rubber cover 104 which encloses a lever 105 which has a narrow central portion seated in a longitudinal groove in the enlarged annular portion 61a of the barrel housing tube 61. The lever has a bent end 105a positioned in an opening 61b of the tube 61 so as to engage a safety pad sleeve 111 and frictionally restrain rotation of such sleeve relative to the barrel housing assembly. As discussed below, the sleeve 111 may be withdrawn from the barrel housing assembly. The other end of the lever 105 extends to the exterior of the rubber cover 104 to enable the bent end 165a to be moved out of the path of the sleeve 111 when it is reinserted in the barrel housing.

The barrel tube 88 as seen in Figure 1 is threaded at its outer end to engage the threaded end 106 of the barrel 23 and has an annular'shoulder 87 intermediate its ends. The shoulder 87.has an annular groove 107 for engagement by a spring-urged latch pawl 108 having a spring 109 which urges the latch pawl toward the notch when the safety pad sleeve 111 is withdrawn from between these two parts. This safety pad sleeve 111 is recessed in and secured to the safety pad structure 26, which structure is urged against a stop nut or disc adaptor 112 on the barrel 23 by a safety pad spring 113. When it is desired to change safety pads or to remove the safety pad for any reason, the nut 112 is removed and the sleeve 111 withdrawn. The latch 108 then engages in the groove 107, and if an attempt is made to condition the tool for firing by compressing the spring 86, the latch prevents forward movement of the handle part 20, the firing action portion 21, and the barrel housing assembly 24, toward the muzzle of the barrel. The latch 108 thus prevents firing of the tool in the absence of the safety pad. The spring 113 permits limited rearward movement 'of the safety 'pad with respect to the rhuizle end of the barrel to enable the muzzle end of the barrel to be pressed against a work surface. This safety pad comprises an insert plate 116 with respect to which the sleeve is secured in eccentric position, and this plate 116 has rotatively mounted thereon in eccentric relation a main guard plate 117. The main guard plate 117 as seen in Figure 14 is provided with four recesses 118 about the periphery of the inner opening thereof for frictional engagement by an index spring 119. This index spring 119 has a coil positioned about the guard button 121 and is in a concealed position between the inner or insert plate 116 and the guard top plate 122, so as to be free from the particles loosened by insertion of a stud.

To enable firing into recesses, such as electrical junction boxes for example, the disc adaptor 112 (Fig. 11) is removed from the end of the barrel 23 and a barrel extension 125 is threaded onto the barrel 23 and receives the disc adapter 112 at its outer end. As shown in Fig. 11, the extension barrel 125 is provided with a series of longitudinally and circumferentially spaced ports 126 for escape of gases. In Fig. 11 the tool is shown with the safety pad 26 in place against the open end of the junction box 123 and the barrel extension is engaging the wall of the junction box which is to be secured to the surface 124-. When the barrel extension 125 is not in use, it may be stored in the recess 33 in the handle 31.

In the operation of the tool, it is first brought to load ing position by pivoting the handle portion 20 and attached action housing assembly 39 with the breech block 66 contained therein laterally about the pin 77 with respect to the barrel block 76 and barrel assembly to and past the positions shown in Figs. 8 and 10. The pivoting is accomplished by first pulling the handle portion 20 rearwardly with respect to the barrel-housing assembly 24. This pulls all portions of the tool, including the action housing assembly 39, the breech block 66, the barrel block 76, the barrel 23 and the barrel sleeve 88 (Fig. 1) rearwardly as a unit with respect to the barrel housing assembly to compress the spring 86. That is to say, the barrel housing assembly 24, in effect, moves forwardly with respect to the remainder of the tool, including the action housing assembly 39, to remove the end of the tang 64 (Figs. 8 and of the barrel housing assembly 24 (see also Fig. 1) from beneath the sleeve 51 of the action housing assembly 39. This unlocks the action housing assembly 39 from the barrel housing assembly and enables the breech block 66 contained in and fitting the action housing assembly. including the yoke portions 67 and 68 of the breech block, to pivot relative to the barrel block 76 about the pin 77. Such pivoting movement causes the pawl 102 (Figs. 3 and 10), which is carried by the breech block 66, to engage the pin 93, which is carried by the extractor 92 in the barrel block 76, to slide the extractor in the barrel block 76 against the action of the spring 94 (Fig. 3) and move the extractor head 91 to and past the position shown in Figs. 8 and 10. Any cartridge 28 which is present in the barrel of the gun is thus extracted. Continued pivoting movement of the breech block 66 with respect to the barrel block 76 about the pin 77 carries the pawl 102 past the pin 93 to allow the spring 94 (Fig. 3) to return the extractor 92 to its retracted position in the barrel block 76.

A stud, such as the stud 27 of Fig. 1, can then be inserted in the barrel while the tool is in its fully pivoted or broken open position and also a cartridge, such as the cartridge 28 of Fig. 1, can also be inserted in the chamber in the barrel. The tool is then closed by the reverse of the pivoting movement above described. The pawl 102 (Fig. 10) pivots about its pin 103 to pass the pin 93 carried by the extractor 92. The breech block 66 comes into alignment with the barrel block 76 and the barrel housing assembly 24, urged by the spring 86 slides a short distance rearwardly with respect to the remainder of the tool including the breech and barrel blocks to again engage the end of the tang 64 (Figs. 5, 8 and 12) of the barrel housing assembly 24 underneath the sleeve 51 of the action housing assembly 39. This locks the tool against being broken open until the handle portion 20 and action housing assembly 39 is again pulled rearwardly with respect to the barrel housing assembly 24 to remove the end of the tang 64 from beneath the sleeve 51.

The tool is now ready to be employed to drive the stud 27 present in the barrel 23. It cannot be fired until the muzzle of the barrel 23 is pressed against a work surface by the handle portion 20 with sutficent force to compress the spring 86 and cause the barrel housing assembly 24, the action housing assembly 39 and the handle portion 20 to move forwardly with respect to the barrel 23, barrel block 76 and breech block 66 from the position shown in Fig. 1 to the position shown in Fig. 4 in which the finger 47 of the trigger 42 is above the lower end of the sear plate 48 carried by the breech block 66. During this movement of the handle portion 20, the firing pin 37 is held against forward movement by the sear plate 48 carried by the breech block 66 to cause compression of the firing pin spring 36. Actuation of the trigger moves the sear plate 48 downwardly to the position shown in Fig. 7 to release the firing pin 37 to cause it to be moved by the spring 36 to the position of Fig. 7 to fire the cartridge. The safety pad 26 is held against the surface of the work during firing by the spring 113 (Fig. 1).

After firing the tool is removed from contact with the work surface and again broken open to extract the used cartridge and enable loading as above described. It is impossible to fire the tool when the safety pad 26 and the sleeve 111 secured thereto is removed from the tool, since the latch 108 then engages in the groove 107 in the barrel sleeve 88 to prevent the above-described movement of the barrel 23 and associated parts, which movement is necessary to condition the tool for firing, as also above described.

While I have shown and described a preferred embodiment of the invention, it is apparent that the invention is capable of variation and modification from the form shown so that the scope thereof should be limited only by the scope of the claims appended hereto.

I claim:

1. An explosively actuated stud driving tool comprising a front portion including a barrel block and a barrel having its rear end extending through said barrel block, and a rear portion including a handle part and a breech block in the form of an integral yoke member having yoke portions extending forwardly and embracing said barrel block, the axis of said barrel and said end of said barrel extending between said yoke portions, a pivot pin connecting said breech block to said barrel block for relative pivotal movement of said portions between a closed position and an open position of said portions, said rear portion having a part thereof in alignment with the longitudinal axis of said barrel and a handle part extending at an angle to said longitudinal axis-when said ass-zest I T! l portions are in said closed position relative to eachother, said pivot pin being spaced laterally from said longitudinal axis and extending perpendicularly to said longitudinal axis and parallel to a plane passing through said longitudinal axis and centrally through said handle part when said portions are in said closed position relative to each other, and releasable locking means for locking said portions together against said relative pivotal movement when said portions are in said closed position, said locking means including an external sleeve carried by one of said portions and an element slidably carried by the other of said portions on the side of said tool opposite said pivot pin for sliding movement longitudinally of said other of said portions so as to releasably engage under said sleeve.

2. An explosively actuated stud driving tool comprising a front portionincluding a barrel block and a barrel having its rear end extending through said barrel block, and a rear portion including a handle part and a breech block in the form of an integral yoke member having yoke portions extending forwardly and embracing said barrel block, the axis of said barrel and said end of said barrel extending between said yoke portions, a pivot pin connecting said breech block to said barrel block for relative pivotal movement of said portions between a closed position and an open position of said portions, said rear portion having a part thereof in alignment with the longitudinal axis of said barrel when said portions are in said closed position relative to eachother, said pivot pin being spaced laterally from the longitudinal axis of said barrel and extending perpendicularly to said longitudinal axis, and releasable locking means for looking said portions together against said relative pivotal movement when said portions are in said closed position relative to each other, said locking means including an external sleeve carried by one of said Portions and an element slidably carried by the other of said portions on the side of said tool opposite said pivot pin for sliding movement longitudinally of said other of said portions so as to releasably engage under said sleeve.

3. An explosively actuated stud driving tool comprising a front portion including a barrel and a rear portion including a handle part, a pivot pin connecting said rear portion to said front portion for relative pivotal move ment of said portions between a closed position and an open position of said portions, said rear portion having a part thereof in alignment with the longitudinal axis of said barrel when said portions are in said closed position relative to each other, said pivot pin being spaced laterally from said longitudinal axis and extending perpendicularly to said longitudinal axis, said front portion also including a barrel housing assembly slidably mounted on said barrel for movement longitudinally of said barrel, a spring positioned beti een said barrel housing assembly and said barrel to urge said barrel housing assembly toward said rear portion of saidtool with respect to said barrel, a locking element carried by said barrel housing assembly and interengaging with said rear portion to lock said rear portion to said front portion against said pivotal movement when said front and rear portions are in said closed position relative to each other, said lockingelement being releasable from said rear portion upon sliding movement of said barrel housing assembly longitudinally on said barrel away from said rear portion of said tool to compress said spring to thereby enable pivotal movement of said front and rear portions relative to each other to said open position, said rear portion having a sleeve in alignment with said barrel housing assembly when said front and rear portions are in said closed position relative to each other, the rear portion of said barrel terminating in a barrel block over which said sleeve is slidable forwardly to enable said rear portion to move forwardly to a firing position relative to said-barrel block and to further look said rear portion relative to said front portion-againstsaid pivotal movement when the muzzle of said barrel is pressed against a work surface by pres sure exerted through said rear portion to compress said spring, a firing pin and a firing pin spring positioned in said rear portion, means positioned in said rear portion and heldrby said barrel block against forwardmovernent, the last named means having an element engaging said firing pin to load said firing pin spring, and manual means for releasing said firing pin to fire said tool when said rear portion of said tool reaches said firing position relative to said barrel block.

4. An explosively actuated stud driving tool comprising a front portion including a barrel assembly and a rear portion including a handle part, a pivot pin connecting said rear portion to said front portion for relative pivotal movement of said portions between a closed position and an open position of said portions, said rear portion having a part thereof in alignment with the longitudinal axis of said barrel when said portions are in said closed position relative to each other, said pivot pin being spaced laterally from said longitudinal axis and extending perpendicularly to said longitudinal axis, said front portion also including a barrel housing assembly slidably mounted on said barrel assembly for movement longitudinally of said barrel, a spring positioned between said barrel housing assembly and said barrel assembly to urge said barrel housing assembly toward said rear portion of said tool with respect to said barrel assembly, a locking element carried by 'said barrel housing assembly and interengaging with said rear portion to lock said rear portion to said front portion against said pivotal movement when said front and rear portions are in said closed position relative to each other, said locking element being releasable from said rear portion upon sliding movement of said barrel housing assembly longitudinally on said barrel assembly away from said rear portion of said tool to compress said spring to thereby enable pivotal movement of said front and rear portions relative to each other to said open position, said rear portion having a sleeve in alignment with said barrel housing assembly when said front and 'rear portions are in said closed position relative to each other, the rear portion of said barrel assembly terminating in a barrel block over which said s eeve is slidable forwardly to enable said rear portion to move forwardly to a firing position relative to said barrel block and to further lock said rear portion relative to said front portion against said pivotal movement when the muzzle of said barrel assembly is pressed against a work surface by pressure exerted through said rear portion to compress said spring, said sleeve engaging said barrel housing assembly to move said barrel housing assembly forwardly relative to said barrel assembly, a firing pin and a firing pin spring positioned in said rear portion, means positioned in said rear portion and held by said barrel block against forward movement, the last named means having an element engaging said firing pin to load said firing pin spring, a removable safety shield adjacent said muzzle end of said barrel assembly and having a safety shield sleeve extending rearwardly of said tool around said barrel assembly and into said barrel housing assembly, and locking means positioned within said barrel housing assembly, said locking means being carried by one of said assemblies and engaging the other of said assemblies for locking said barrel housing assembly against forward movement relative to said barrel assembly to prevent loading of said firing pin spring when said safety shield is removed from said tool, said safety shield sleeve having a portion positioned between said locking means and the other of said assemblies to hold said looking means out of engagement with said other assembly when said safety shield is in position on said tool.

5. An explosively actuated stud driving tool comprising a front portion including a barrel member and a rear portion connected to said front portion for pivotal move menta'bout an axis transverse of said barrel member having anaction housing movable forwardly with respect to said barrel member to lock said portions against said pivotal movement, said front portion including a barrel housing assembly mounted on said barrel member for movement forwardly with respect to said barrel member, a spring positioned between said barrel housing assembly and said barrel member to urge said barrel housing assembly rearwardly toward said action housing with respect to said barrel member, said barrel housing assembly being movable forwardly with respect to said barrel member by said action housing against the action of said spring when the muzzle end of said too is pressed against a Work surface by pressure exerted through said action housing, a firing pin and a firing pin spring positioned in said action housing, said firing pin spring being loaded to condition it for actuating said firing pin when said action housing is moved forwardly with respect to said barrel member, a removable safety shield adjacent said muzzle end of said tool and having a sleeve extending rearwardly of said tool around said barrel member and into said barrel housing assembly, and locking means positioned within said barrel housing member said locking means being carried by said barrel housing assembly and engaging said barrel member to lock said barrel housing assembly against forward movement relative to said barrel member to prevent loading of said firing pin spring when said safety shield is removed from said tool, said sleeve having a portion positioned between said locking means and said barrel member to hold said locking means out of engagement with said barrel member when said safety shield is in position on said tool.

6. An explosively actuated stud driving tool comprising a front portion including a barrel member and a rear portion, said front portion including a housing member mounted on said barrel member for movement longitudinally of said barrel member, a spring positioned between said housing member and said barrel member to urge said housing member toward said rear portion with respect to said barrel member, said rear portion being movable forwardly with respect to said barrel member to move said housing member forwardly with respect to said barrel member against the action of said spring when the muzzle end of said tool is pressed against a work surface by pressure exerted through said rear portion, a firing pin and a firing pin spring positioned in said rear portion, said firing pin spring being loaded to condition it for actuating said firing pin when said rear portion is moved forwardly with respect to said barrel member, a removable safety shield adjacent said muzzle end of said tool and having a sleeve extending rearwardly of said tool around said barrel member and into said housing memher, and locking means positioned Within said housing member and pivotally carried by one of said members, said lock being resiliently urged into locking engagement with the other of said members to lock said housing member against forward movement relative to said barrel member to prevent loading of said firing pin spring when said safety shield is removed from said tool, said sleeve having a portion positioned-between said locking means and said other member to hold said locking means out of said engagement with said other of said members by said sleeve when said safety shield is in position on said tool.

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